Hi. I have a 2004 Tacoma Prerunner 2.7 L 3RZ engine rattle or clatter that happens first thing in the morning. This rattle gets longer with colder mornings. It started maybe last year and now I am reminded of it.

The truck has 150k and oil level is at full. I have been running synthetic valvoline and mobil 1 since day 1 with the truck.

It runs perfectly fine. Just this weird unusual rattle that goes away once it warms up. I have seen other and older posts relating to a possible piston slap? Others have also said this is normal for this engine. And my dad listened to it and said it is in need of a valve job.

Something you can try is to turn on the air cond. during this sound and see if the rattle stops. Thinking of the electric clutch rattling on the air cond. compressor. If the rattle stops immediately, the electric clutch is your culprit. If the rattle continues then you can omit the air cond. clutch as a culpret.

Def not the particular Toyota tick, would get this checked out. Mine makes a low tapping sound on cold mornings but goes away as soon as its warmed up. Yours sounds like a rod knocking, but I doubt that's what it is. If it was a rod knock it would be doing it all the time regardless of engine temp.

mines has a similar sound, I have a 2012 with 5k miles and I always have a rattle during cold starts cept mines seems to be coming from the muffler area. took it to the dealership and they had no idea what the problem is so they put some insulation or something on the spare tire chain to see if that helps from eliminating the rattle and it still rattles on cold starts in the morning.

You've had it since day one -- how long has it been making this noise? Has it always made this noise but it's just getting louder now so you are becoming concerned? Anyway I agree it's probably piston slap... nothing to worry about, just don't rev the motor too high until it gets mostly warmed up. High revs are not good for cold engines.

You definitely have something going on however it sounds too much like "tin" instead of a solid rod knock or piston slap. Try to rule out the AC clutch and exhaust pipe vibration. If you are using 05/30 oil try 00/30 see if that helps. You're not in really cold weather so perhaps something as simple as oil might help. Please let us know how this turns out, I'm interested as I have a 2.7L also although I'm just getting broke in at 44K miles.
Bill

But yes I have had this truck since day one and it never made this sound. I heard it first around last winter maybe January-February but did not think much of it since it goes away. And as the winter turned to spring then summer, the cold mornings were not as cold so that rattling noise does not happen. But now that it is getting colder again and the truck's mileage is getting higher, I am getting concerned. To top that off was my discovery of TacomaWorld so here I am asking for input.

It gets frustrating though. I'm not mechanic savy but I have some experience doing simple repairs which I learned during my roommate situation. All I know is that if it's a warm or mild morning, this rattling doesn't happen. If it's a damn cold morning where you feel like you fingers are going to fall off, the rattling happens. I also live in a condo complex with no garage so extensive mechanical work is out of the question otherwise I can get fined ($100-200) if caught.

I will plan on leaving this car overnight on a cold night at the mechanics (a close relationship since this mechanic's parents are good friends with my boss's parents and I have a good relationship with my boss) and bring the suggestions listed here to see if that helps to point him in the right direction. Because once the truck becomes warm, the rattling stops and we would have to wait again for another cold morning.

I am going to update it I find out anything. This prerunner has been a gem taking my family and I up and down the states so I definitely plan on getting it taken care of ASAP. Just waiting for the truck's next service and saving up some cash.

This is the same exact sound my 04 3rz doublecab makes. It's very frustrating trying to pinpoint where the noise is coming from. My truck has 127k miles. Although my happens when I put it in reverse and drive. I have to warm it up too for at least 1 min. Let me know after your mechanic finds out the culprit.

Hi. I have a 2004 Tacoma Prerunner 2.7 L 3RZ engine rattle or clatter that happens first thing in the morning. This rattle gets longer with colder mornings. It started maybe last year and now I am reminded of it.

The truck has 150k and oil level is at full. I have been running synthetic valvoline and mobil 1 since day 1 with the truck.

It runs perfectly fine. Just this weird unusual rattle that goes away once it warms up. I have seen other and older posts relating to a possible piston slap? Others have also said this is normal for this engine. And my dad listened to it and said it is in need of a valve job.

Same deal here, if it's not a major mech. thing, try Amsoil 0w-30. Mobile 1 is a group III and not really synthetic. Amsoil is a group IV and far superior to Exxon etc.

Amsoil uses Mobil-1 base stocks.

Their additive package is different, but the base oils are identical.

Pretty much all automotive synthetics have been Group-3 blends ever since Mobil lost the Castrol lawsuit. The only fully group-4 synthetics still offered by Mobil or Amsoil are their motorcycle blends.

Wish I would of seen this sooner mine does the same thing 01-2.7 200K on it now. But mine even did it during the spring when leaving work it wouldn't rattle on start up but on acceleration from parking spot it would. I could let up on it and it would stop, push gas down again and it would knock. But this would stop within 2 city blocks.